A total cholesterol level of 240 or above is dangerous, because it means the individual has a greater chance of developing heart disease, according to Everyday Health. Higher numbers indicate increased risk.
A patient's total cholesterol level is considered in conjunction with other test results. High-density lipoprotein, or HDL, is a healthy cholesterol, explains Everyday Health. In this case, higher numbers help reduce the possibility of heart disease. A level above 60 milligrams per deciliter is the goal, while anything under 40 is potentially unsafe.
Levels of the "bad" cholesterol, known as low-density lipoprotein, or LDL, should be kept low, explains Everyday Health. Levels of 190 milligrams per deciliter or above are very hazardous. Under 100 is the target range for preventing heart disease.